re: I read an interesting paper a while back....
Do you have that paper online or can point to it?
Sorry- It was a paper I accessed at my last job.... The great thing about the last place I worked was that we had access to pretty much every online technical and scientific journal available... I do remember that I was searching for articles that addressed the Fermi Paradox, and I am fairly certain it was in an astronomy (peer reviewed) journal.
If there are billions of habitable planets in our galaxy alone, the GRBs and SNs can't "get" them all.
I would hope not! But a GRB could take out a sizeable neghborhood in our galaxy.